The 89th Prime Minister of Japan, the main protagonist of the story. Armed with a natural talent for mahjong, passed down from his grandfather Matajiro Koizumi, Junichiro defends Japanese interests and integrity against the heads of the world's superpowers, even after his retirement from politics. Signature skills include "Goumoupai" (轟盲牌, scraping tiles with a tight grip to make white tiles), and "Rising Sun" (Thirteen orphans).